He described the conviction of the five fertiliser bomb plotters, jailed for life at the Old Bailey earlier this week for a conspiracy to cause explosions, as a "triumph" for both the police and the security service MI5.

Sir Ian condemned the "counsel of perfection" that had voiced criticism over links between that gang and two of the 7 July bombers.

During the trial it emerged that MI5 had spotted Mohammad Sidique Khan and Shehzad Tanweer, two of the bombers, on four occasions in 2004 with at least one of the conspirators of the fertiliser bomb plot.

However, the two who went on to bomb London a year later were not investigated further.

Police praise

"The first thing to say is that trial and those convictions were a triumph, a triumph for the intelligence service and triumph for the police," Sir Ian said.

"Put it bluntly, the naysayers are those who decided the real story is the connection with the terrible events we are describing here [the 7 July attacks].

"We have no reason to criticise the families or the survivors who must be looking for an explanation.

"But we have also got to balance the courage that has arrived at the convictions.

"What I want you to understand through 7/7 and 21/7 is these are acts of bravery, of persistence, of compassion on a scale almost unheard of.